Core: Use extra thread for Cubeb on Windows to not disturb the CoInitialize state of whatever thread happens to call a Cubeb function.

Source/Core/AudioCommon/CubebStream.cpp

@@ -7,10 +7,16 @@
 
 #include "AudioCommon/CubebUtils.h"
 #include "Common/CommonTypes.h"
+#include "Common/Event.h"
 #include "Common/Logging/Log.h"
+#include "Common/ScopeGuard.h"
 #include "Common/Thread.h"
 #include "Core/Config/MainSettings.h"
 
+#ifdef _WIN32
+#include <Objbase.h>
+#endif
+
 // ~10 ms - needs to be at least 240 for surround
 constexpr u32 BUFFER_SAMPLES = 512;
 
@@ -31,12 +37,37 @@ void CubebStream::StateCallback(cubeb_stream* stream, void* user_data, cubeb_sta
 {
 }
 
+CubebStream::CubebStream()
+#ifdef _WIN32
+    : m_work_queue([](const std::function<void()>& func) { func(); })
+{
+  Common::Event sync_event;
+  m_work_queue.EmplaceItem([this, &sync_event] {
+    Common::ScopeGuard sync_event_guard([&sync_event] { sync_event.Set(); });
+    auto result = ::CoInitializeEx(nullptr, COINIT_MULTITHREADED | COINIT_DISABLE_OLE1DDE);
+    m_coinit_success = result == S_OK;
+  });
+  sync_event.Wait();
+}
+#else
+    = default;
+#endif
+
 bool CubebStream::Init()
 {
-  m_ctx = CubebUtils::GetContext();
-  if (!m_ctx)
-    return false;
+  bool return_value = false;
 
+#ifdef _WIN32
+  if (!m_coinit_success)
+    return false;
+  Common::Event sync_event;
+  m_work_queue.EmplaceItem([this, &return_value, &sync_event] {
+    Common::ScopeGuard sync_event_guard([&sync_event] { sync_event.Set(); });
+#endif
+
+    m_ctx = CubebUtils::GetContext();
+    if (m_ctx)
+    {
       m_stereo = !Config::ShouldUseDPL2Decoder();
 
       cubeb_stream_params params{};
@@ -59,33 +90,76 @@ bool CubebStream::Init()
         ERROR_LOG_FMT(AUDIO, "Error getting minimum latency");
       INFO_LOG_FMT(AUDIO, "Minimum latency: {} frames", minimum_latency);
 
-  return cubeb_stream_init(m_ctx.get(), &m_stream, "Dolphin Audio Output", nullptr, nullptr,
+      return_value =
+          cubeb_stream_init(m_ctx.get(), &m_stream, "Dolphin Audio Output", nullptr, nullptr,
                             nullptr, &params, std::max(BUFFER_SAMPLES, minimum_latency),
                             DataCallback, StateCallback, this) == CUBEB_OK;
+    }
+
+#ifdef _WIN32
+  });
+  sync_event.Wait();
+#endif
+
+  return return_value;
 }
 
 bool CubebStream::SetRunning(bool running)
 {
   bool return_value = false;
-  CubebUtils::RunInCubebContext([&] {
+
+#ifdef _WIN32
+  if (!m_coinit_success)
+    return false;
+  Common::Event sync_event;
+  m_work_queue.EmplaceItem([this, running, &return_value, &sync_event] {
+    Common::ScopeGuard sync_event_guard([&sync_event] { sync_event.Set(); });
+#endif
     if (running)
       return_value = cubeb_stream_start(m_stream) == CUBEB_OK;
     else
       return_value = cubeb_stream_stop(m_stream) == CUBEB_OK;
+#ifdef _WIN32
   });
+  sync_event.Wait();
+#endif
+
   return return_value;
 }
 
 CubebStream::~CubebStream()
 {
-  CubebUtils::RunInCubebContext([&] {
-    SetRunning(false);
+#ifdef _WIN32
+  Common::Event sync_event;
+  m_work_queue.EmplaceItem([this, &sync_event] {
+    Common::ScopeGuard sync_event_guard([&sync_event] { sync_event.Set(); });
+#endif
+    cubeb_stream_stop(m_stream);
     cubeb_stream_destroy(m_stream);
+#ifdef _WIN32
+    if (m_coinit_success)
+    {
+      m_coinit_success = false;
+      CoUninitialize();
+    }
   });
+  sync_event.Wait();
+#endif
   m_ctx.reset();
 }
 
 void CubebStream::SetVolume(int volume)
 {
-  CubebUtils::RunInCubebContext([&] { cubeb_stream_set_volume(m_stream, volume / 100.0f); });
+#ifdef _WIN32
+  if (!m_coinit_success)
+    return;
+  Common::Event sync_event;
+  m_work_queue.EmplaceItem([this, volume, &sync_event] {
+    Common::ScopeGuard sync_event_guard([&sync_event] { sync_event.Set(); });
+#endif
+    cubeb_stream_set_volume(m_stream, volume / 100.0f);
+#ifdef _WIN32
+  });
+  sync_event.Wait();
+#endif
 }

Source/Core/AudioCommon/CubebStream.h

@@ -4,16 +4,23 @@
 #pragma once
 
 #include <cstddef>
+#include <functional>
 #include <memory>
 #include <vector>
 
 #include "AudioCommon/SoundStream.h"
+#include "Common/WorkQueueThread.h"
 
 #include <cubeb/cubeb.h>
 
 class CubebStream final : public SoundStream
 {
 public:
+  CubebStream();
+  CubebStream(const CubebStream& other) = delete;
+  CubebStream(CubebStream&& other) = delete;
+  CubebStream& operator=(const CubebStream& other) = delete;
+  CubebStream& operator=(CubebStream&& other) = delete;
   ~CubebStream() override;
   bool Init() override;
   bool SetRunning(bool running) override;
@@ -27,6 +34,11 @@ private:
   std::vector<short> m_short_buffer;
   std::vector<float> m_floatstereo_buffer;
 
+#ifdef _WIN32
+  Common::WorkQueueThread<std::function<void()>> m_work_queue;
+  bool m_coinit_success = false;
+#endif
+
   static long DataCallback(cubeb_stream* stream, void* user_data, const void* /*input_buffer*/,
                            void* output_buffer, long num_frames);
   static void StateCallback(cubeb_stream* stream, void* user_data, cubeb_state state);

Source/Core/AudioCommon/CubebUtils.cpp

@@ -16,49 +16,6 @@
 
 #include <cubeb/cubeb.h>
 
-#ifdef _WIN32
-#include <Objbase.h>
-#endif
-
-// On Windows, we must manually ensure that COM is initialized in MTA mode on every thread that
-// accesses the cubeb API. See the comment on cubeb_init in cubeb.h
-// We do this with a thread-local variable that keeps track of whether COM is initialized or not,
-// and initialize it if it isn't. When the thread ends COM is uninitialized again.
-#ifdef _WIN32
-namespace
-{
-class auto_com
-{
-public:
-  auto_com() = default;
-  auto_com(const auto_com&) = delete;
-  auto_com(auto_com&&) = delete;
-  auto_com& operator=(const auto_com&) = delete;
-  auto_com& operator=(auto_com&&) = delete;
-  ~auto_com()
-  {
-    if (m_initialized)
-    {
-      CoUninitialize();
-    }
-  }
-  bool initialize()
-  {
-    if (!m_initialized)
-    {
-      HRESULT result = CoInitializeEx(nullptr, COINIT_MULTITHREADED | COINIT_DISABLE_OLE1DDE);
-      m_initialized = SUCCEEDED(result);
-    }
-    return m_initialized;
-  }
-
-private:
-  bool m_initialized = false;
-};
-}  // namespace
-static thread_local auto_com tls_com_context;
-#endif
-
 static ptrdiff_t s_path_cutoff_point = 0;
 
 static void LogCallback(const char* format, ...)
@@ -92,38 +49,8 @@ static void DestroyContext(cubeb* ctx)
   }
 }
 
-static bool EnsureCubebCallable()
-{
-#ifdef _WIN32
-  if (!tls_com_context.initialize())
-    return false;
-#endif
-  return true;
-}
-
-void CubebUtils::RunInCubebContext(const std::function<void()>& func)
-{
-  // Cubeb is documented to require MTA COM mode, so if the current thread was initialized in STA
-  // mode, we make a temporary thread to execute the cubeb call.
-  if (EnsureCubebCallable())
-  {
-    func();
-  }
-  else
-  {
-    std::thread([&] {
-      // this should never fail, so yell loudly if it does
-      ASSERT(EnsureCubebCallable());
-      func();
-    }).join();
-  }
-}
-
 std::shared_ptr<cubeb> CubebUtils::GetContext()
 {
-  if (!EnsureCubebCallable())
-    return nullptr;
-
   static std::weak_ptr<cubeb> weak;
 
   std::shared_ptr<cubeb> shared = weak.lock();

Source/Core/AudioCommon/CubebUtils.h

@@ -10,6 +10,5 @@ struct cubeb;
 
 namespace CubebUtils
 {
-void RunInCubebContext(const std::function<void()>& func);
 std::shared_ptr<cubeb> GetContext();
 }  // namespace CubebUtils

Source/Core/Core/HW/EXI/EXI_DeviceMic.cpp

@@ -12,27 +12,59 @@
 #include "AudioCommon/CubebUtils.h"
 #include "Common/Common.h"
 #include "Common/CommonTypes.h"
+#include "Common/Event.h"
 #include "Common/Logging/Log.h"
+#include "Common/ScopeGuard.h"
 
 #include "Core/CoreTiming.h"
 #include "Core/HW/EXI/EXI.h"
 #include "Core/HW/GCPad.h"
 #include "Core/HW/SystemTimers.h"
 
+#ifdef _WIN32
+#include <Objbase.h>
+#endif
+
 namespace ExpansionInterface
 {
 void CEXIMic::StreamInit()
 {
-  m_cubeb_ctx = CubebUtils::GetContext();
-
   stream_buffer = nullptr;
   samples_avail = stream_wpos = stream_rpos = 0;
+
+#ifdef _WIN32
+  if (!m_coinit_success)
+    return;
+  Common::Event sync_event;
+  m_work_queue.EmplaceItem([this, &sync_event] {
+    Common::ScopeGuard sync_event_guard([&sync_event] { sync_event.Set(); });
+#endif
+    m_cubeb_ctx = CubebUtils::GetContext();
+#ifdef _WIN32
+  });
+  sync_event.Wait();
+#endif
 }
 
 void CEXIMic::StreamTerminate()
 {
   StreamStop();
+
+  if (m_cubeb_ctx)
+  {
+#ifdef _WIN32
+    if (!m_coinit_success)
+      return;
+    Common::Event sync_event;
+    m_work_queue.EmplaceItem([this, &sync_event] {
+      Common::ScopeGuard sync_event_guard([&sync_event] { sync_event.Set(); });
+#endif
       m_cubeb_ctx.reset();
+#ifdef _WIN32
+    });
+    sync_event.Wait();
+#endif
+  }
 }
 
 static void state_callback(cubeb_stream* stream, void* user_data, cubeb_state state)
@@ -68,7 +100,13 @@ void CEXIMic::StreamStart()
   if (!m_cubeb_ctx)
     return;
 
-  CubebUtils::RunInCubebContext([&] {
+#ifdef _WIN32
+  if (!m_coinit_success)
+    return;
+  Common::Event sync_event;
+  m_work_queue.EmplaceItem([this, &sync_event] {
+    Common::ScopeGuard sync_event_guard([&sync_event] { sync_event.Set(); });
+#endif
     // Open stream with current parameters
     stream_size = buff_size_samples * 500;
     stream_buffer = new s16[stream_size];
@@ -101,19 +139,29 @@ void CEXIMic::StreamStart()
     }
 
     INFO_LOG_FMT(EXPANSIONINTERFACE, "started cubeb stream");
+#ifdef _WIN32
   });
+  sync_event.Wait();
+#endif
 }
 
 void CEXIMic::StreamStop()
 {
   if (m_cubeb_stream)
   {
-    CubebUtils::RunInCubebContext([&] {
+#ifdef _WIN32
+    Common::Event sync_event;
+    m_work_queue.EmplaceItem([this, &sync_event] {
+      Common::ScopeGuard sync_event_guard([&sync_event] { sync_event.Set(); });
+#endif
       if (cubeb_stream_stop(m_cubeb_stream) != CUBEB_OK)
         ERROR_LOG_FMT(EXPANSIONINTERFACE, "Error stopping cubeb stream");
       cubeb_stream_destroy(m_cubeb_stream);
-    });
       m_cubeb_stream = nullptr;
+#ifdef _WIN32
+    });
+    sync_event.Wait();
+#endif
   }
 
   samples_avail = stream_wpos = stream_rpos = 0;
@@ -147,7 +195,12 @@ void CEXIMic::StreamReadOne()
 
 u8 const CEXIMic::exi_id[] = {0, 0x0a, 0, 0, 0};
 
-CEXIMic::CEXIMic(int index) : slot(index)
+CEXIMic::CEXIMic(int index)
+    : slot(index)
+#ifdef _WIN32
+      ,
+      m_work_queue([](const std::function<void()>& func) { func(); })
+#endif
 {
   m_position = 0;
   command = 0;
@@ -162,6 +215,16 @@ CEXIMic::CEXIMic(int index) : slot(index)
 
   next_int_ticks = 0;
 
+#ifdef _WIN32
+  Common::Event sync_event;
+  m_work_queue.EmplaceItem([this, &sync_event] {
+    Common::ScopeGuard sync_event_guard([&sync_event] { sync_event.Set(); });
+    auto result = ::CoInitializeEx(nullptr, COINIT_MULTITHREADED | COINIT_DISABLE_OLE1DDE);
+    m_coinit_success = result == S_OK;
+  });
+  sync_event.Wait();
+#endif
+
   StreamInit();
 }
 

Source/Core/Core/HW/EXI/EXI_DeviceMic.h

@@ -6,6 +6,7 @@
 #include <mutex>
 
 #include "Common/CommonTypes.h"
+#include "Common/WorkQueueThread.h"
 #include "Core/HW/EXI/EXI_Device.h"
 
 struct cubeb;
@@ -99,5 +100,10 @@ private:
   int stream_wpos;
   int stream_rpos;
   int samples_avail;
+
+#ifdef _WIN32
+  Common::WorkQueueThread<std::function<void()>> m_work_queue;
+  bool m_coinit_success = false;
+#endif
 };
 }  // namespace ExpansionInterface